1. Technical Field
This invention relates to a receiver and a receiving method.
2. Related Art
In connection with a communication device using a pulse train (described in JP-T-10-508725), a communication device for suppressing interference to another transmission/reception system (described in JP-A-2004-336764) and a communication device for generating a template (pulse train) for synchronization capture (described in JP-A-2004-241927), a transmitter located so as to confront a related-art receiver transmits to the receiver a reception signal containing a fixed number (for example 5) of pulses used for synchronization capture and information which is superposed on the pulses concerned and is to be received by the receiver. Therefore, the receiver performs the synchronization capture by using a template having the same shape as the waveforms of the five pulses.
In the transmitter, the number of pulses may be changed in accordance with the environment under which the transmitter is disposed. For example, when the propagation path between the transmitter and the receiver is not excellent, the number of pulses is increased so that the receiver can surely perform the synchronization capture, and for example, the number of pulses is increased to ten. In other words, when the power of a signal transmitted by another transmitter is faint, in order to avoid the signal transmitted by the transmitter from adversely affecting, that is, interfering in the faint signal transmitted by the other transmitter, the number of pulses is reduced, for example, it is reduced to three.
However, the receiver described above has only the template having the same waveforms as the five pulses, and does not have any other template, and thus there is a problem that when the transmitter transmits a signal containing ten pulses described above or a signal containing three pulses described above, it is impossible to perform synchronization capture on the signal concerned.